Parsley occupies a curious category in the culinary world. It's ubiquitous and yet so often a sort of anti-ingredient. I can't think of any other food so often placed upon a plate with so little concern as to whether it actually gets eaten. It appears on countless dishes – a lonely sprig or, on larger platters, an irritatingly symmetrical pair, quartet or octet – dividing the goujons and lemon wedges, or whatever. At least the lemon wedges might get squeezed.

Then there's the finely chopped parsley finish, minced to death and sprinkled in senselessly small quantities, functioning as a sort of catch-all cosmetic buff-up, the powder on the nose of a dish, a trifling vanity. (It's not always a waste of time to sprinkle chopped parsley on, say, buttered new potatoes, but you need a proper fistful to make it work, and you want proper little flecks of leaf, not grey-green dust.)

While parsley's glorious, deep green hue and wonderful, fresh prettiness certainly do make many things look nicer, using it as mere culinary air-brushing is a lazy, anachronistic foible, and a waste of a fabulous ingredient. I'd be very happy if the chefs of this land used parsley a bit less, and got people to eat it a whole lot more. It's high time we all forgot this leaf's heritage as food tinsel and started appreciating it for the magical vegetable it is.

I say vegetable because, although parsley is traditionally used as a herb, its mild, aromatic, grassy-cool flavour means it can be used in quantity to great effect. I probably eat it as often as a salad leaf, or as the main leafy green in a soup, as I do a herb. And it's really quite hard to go wrong with it. It's rarely going to overpower or ruin a dish, but has the capacity to enhance and define a huge number of other ingredients. (See my little list below for parsley's favourite friends.)

There are two distinct types of parsley: good, old-fashioned curly (Petroselinum crispum) and flat-leaf, also known as French or Italian parsley (P. crispum var. neapolitana). I wouldn't say that curly parsley is inferior, but I do use it much less because its texture is considerably coarser (it's certainly less nice to eat raw) and the flavour somehow a little less refined. It is nevertheless a fine addition to a hearty soup – with ham and split peas, perhaps – it does sterling work when flavouring a stock, and, if finely chopped, is delicious strewn into omelettes or over stews. But it is flat-leaf parsley that I am more deeply involved with. This elegant leaf is one of my very favourite things to find in a salad, to chop and stir into a creamy, savoury béchamel sauce, or to layer lavishly in a sandwich with, say, chunks of soft-centred hard-boiled egg, mayonnaise and gherkins. And, in all cases, generously.

Shop-bought parsley can often be pretty good, especially at this time of year when the British crop is flourishing. You can buy big bunches for not too much in good grocers and farm shops. But, if you catch the parsley bug, it is really easy to grow some of your own. Sow it every few months and you should have a year-round supply. It's best started off in a greenhouse or on a warm windowsill, but then it can go outside in a pot, window box or straight into the ground. Put it somewhere sunny, but don't let it get dry, then keep cutting and picking to promote that luscious, leafy growth.

Having a home-grown supply is the best motivation possible not to insult this glorious herb by perching it pusillanimously down the middle of two rows of upwards-pointing, triangle-cut sandwiches, none of which is lucky enough actually to have any parsley inside it.

Ham and parsley salad with red onions and capers

I cook my own ham hock, because the flavour is always so good, but a chunky bit of ham bought off the bone from a good butcher will do very well, too. If you leave out the ham and the mustardy dressing, the parsley, onion and capers, with a touch of oil, vinegar and seasoning, make for a lovely, refreshing side salad in their own right. Serves four.

Pick the leaves from the bunch of parsley and set aside. Put the stalks in a large saucepan with the ham hock, onion, carrot and celery. Cover with water. Bring to a simmer. Cover and cook at a very gentle simmer for three hours, or until the meat is tender and comes away easily from the bone. Skim off any scum that rises to the surface while it's cooking; you may also have to top up with fresh boiling water from time to time. Remove the ham from the pan and leave to cool.

Remove the skin from the ham hock and pull the meat from the bone. Trim away any sinew or membrane, then cut the meat into bite-sized pieces. (Alternatively, just use 250g ready-cooked ham, cut or torn into bite-size chunks.)

Put the dressing ingredients and some salt and pepper in a jar, and shake to emulsify. Put the parsley leaves in a bowl with the sliced red onion, capers and chunks of ham. Trickle over most of the dressing and toss lightly together. Taste and add more salt and pepper, if needed. Arrange on a big serving platter, or four smaller dishes, finish with a touch more dressing, and serve.

Wilted parsley on toast with a poached egg

Wilted parsley on toast with poached egg: Brief exposure to heat turns parsley into a green veg to rival any other. Photograph: Colin Campbell for the Guardian

With a little cooking to tenderise it, parsley is as delicious as any other green veg when served on toast or bruschetta. Serves two.

Pick over the parsley, removing the coarse stems: you want just the leaves and the fine stems attached immediately to them. Put the parsley in a steamer and steam over boiling water for about five minutes. (Or "wilt" for three or four minutes in a pan with a little simmering water.) Transfer the cooked parsley to a colander or sieve, press with the back of a large spoon to squeeze out excess moisture, then let it steam off for a couple of minutes. Place the parsley on a board and chop roughly, then put in a pan with the butter and some salt and pepper. Heat very gently, tossing once or twice, just until the butter is melted and combined with the parsley, then remove from the heat, cover and keep warm.

Poach the eggs according to your favourite method. This is mine: pour 4-5cm of water into a saucepan and bring to a boil. Meanwhile, break each egg into a cup or ramekin. When the water is at a rolling boil, turn off the heat, and immediately but gently tip the eggs into the water. Clap a lid on the pan, and leave for two and a half to three minutes. Use a slotted spoon carefully to scoop up the eggs, and check that the whites are set, with no jellyish, clear bits – if there are, return the eggs to the water for 30 seconds. Give them a minute in the spoon for the water to drip and steam away – you can also dab them carefully with a piece of kitchen paper to help get rid of the water – then trim off any raggedy bits of white.

While the eggs are poaching, toast the bread, rub lightly with garlic, if you like, trickle with a little olive oil or spread with butter, and put on warmed plates. Top each with first the parsley and then an egg, sprinkle on a little salt and pepper, and serve.

Some other things to do with parsley

Parsley loves garlic, and their marriage rarely fails to be a happy one. Very finely chopped parsley combined with very finely chopped raw garlic is known in French cuisine as persillade. Used raw, it makes a fine finish to roasted veg or grilled fish. Alternatively, add some persillade to a sauce, a soup or some roasting chicken pieces a few minutes before the end of cooking, for a slightly more mellow infusion of flavour.

Add some finely grated lemon zest to the basic persillade mix and you get the Italian gremolata, an even zingier affair that's traditionally used to finish osso buco (braised veal shanks), but it's also great on risottos and, again, roast veg.

In a similar vein, a homemade, garlicky mayonnaise, stirred through with lavish amounts of finely chopped parsley, is fantastic with fish, new potatoes, chicken, egg-based salads or green beans.

I love a parsley pesto, too. Use flat-leaf parsley in combination with the more traditional basil in any basic pesto recipe, or dispense with the basil altogether – a parsley, walnut and mature goat's cheese pesto, all bound with rapeseed oil, is a joy.

Use parsley in a summery pea soup in place of the more usual mint. And use much more parsley than you would mint – a good fistful.

Finally, one of my favourite standby salads: simmer puy lentils in stock or water, with a bay leaf, a wedge of onion and the stalks of the parsley you're going to add later, until tender but nutty – about 20 minutes. Leave to cool. Then toss with picked-over parsley leaves and a mustardy vinaigrette (such as the one in the ham hock salad above). That's great with fish, pork and chicken, and leftovers of either.